Impact of use of phosphodiesterase type 5 inhibitors (PDE5-I) after radical prostatectomy (RP) on biochemical recurrence-free (BCRF) and overall survival (OS): A retrospective study from the Northwestern University SPORE in prostate cancer.

Abstract

27 Background: The correlation between PDE5-I use to improve erectile function post RP and BCRF and OS on prostate cancer (PCa) patients (pts) has yielded conflicting results among prior retrospective cohort studies (Michl, 2015). Recent data suggests that these drugs may have an impact on immunity that may explain possible benefits. This study’s purpose was to determine whether PDE5-I use affects BCRF and OS for pts treated with RP for PCa. Methods: This is an IRB approved retrospective cohort study analyzing a subset of pts consented to the SPORE in PCa at Northwestern University’s Lurie Cancer Center. Inclusion criteria included men diagnosed with PCa and treated with RP with curative intent between 2003-2015. Study population (n = 2,410) showed 834 (34.6%) received a PDE5-I post-RP, while 1,576 (65.4%) did not. Pts were grouped based on PDE5-I use and no PDE5-I use after RP. A PDE5-I user must have filled at least 2 prescriptions or completed at least 2 inpatient administrations of a PDE5-I. Continuous variables were summarized by descriptive statistics and differences between groups were assessed via the Wilcoxon rank sum test. Categorical variables were reported by frequencies and percentages and compared via Fisher’s exact test. OS and BCRF survival were summarized for 10-yr rates using Kaplan-Meier estimates. The difference in BCRF and OS between groups was evaluated via log-rank test. Results: Mean age at RP was 60, and 90.95 % were Caucasian. Except for pairwise comparisons for significance of Gleason 3+3 vs. 3+4 histology with higher prevalence of 3+4 in the PDE5-I group (p = 0.0004) and a higher percent of clinical stage T2b-c than T2a in the no PDE5-I group (p = 0.01), no differences were noted in demographics. The 10-yr BCRF survival among PDE5-I users was 92.53% compared to 79.63% among non-users after RP (p < 0.0001). The 10-yr OS rate among PDE5-I users was 97.22% compared to 92.69% among non-users (p = 0.008). Conclusions: This retrospective analysis suggests that PDE5-I use improves biochemical recurrence free survival and overall survival in pts treated with RP for PCa.